/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.hcatalog.hbase.snapshot.lock;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Represents an ephemeral znode name which has an ordered sequence number
 * and can be sorted in order
 *  This class has been used as-is from the zookeeper 3.4.0 recipes with a
 *  change in package name.
 */
public class ZNodeName implements Comparable<ZNodeName> {
  private final String name;
  private String prefix;
  private int sequence = -1;
  private static final Logger LOG = LoggerFactory.getLogger(ZNodeName.class);

  public ZNodeName(String name) {
    if (name == null) {
      throw new NullPointerException("id cannot be null");
    }
    this.name = name;
    this.prefix = name;
    int idx = name.lastIndexOf('-');
    if (idx >= 0) {
      this.prefix = name.substring(0, idx);
      try {
        this.sequence = Integer.parseInt(name.substring(idx + 1));
        // If an exception occurred we misdetected a sequence suffix,
        // so return -1.
      } catch (NumberFormatException e) {
        LOG.info("Number format exception for " + idx, e);
      } catch (ArrayIndexOutOfBoundsException e) {
        LOG.info("Array out of bounds for " + idx, e);
      }
    }
  }

  @Override
  public String toString() {
    return name.toString();
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    ZNodeName sequence = (ZNodeName) o;

    if (!name.equals(sequence.name)) return false;

    return true;
  }

  @Override
  public int hashCode() {
    return name.hashCode() + 37;
  }

  public int compareTo(ZNodeName that) {
    int answer = this.prefix.compareTo(that.prefix);
    if (answer == 0) {
      int s1 = this.sequence;
      int s2 = that.sequence;
      if (s1 == -1 && s2 == -1) {
        return this.name.compareTo(that.name);
      }
      answer = s1 == -1 ? 1 : s2 == -1 ? -1 : s1 - s2;
    }
    return answer;
  }

  /**
   * Returns the name of the znode
   */
  public String getName() {
    return name;
  }

  /**
   * Returns the sequence number
   */
  public int getZNodeName() {
    return sequence;
  }

  /**
   * Returns the text prefix before the sequence number
   */
  public String getPrefix() {
    return prefix;
  }
}
